A virtual universe (VU) is an interactive simulated environment accessed by multiple users through an online interface. Users inhabit and interact in the VU via avatars, which are a user's representation of himself or herself. These representations can be in the form of a three-dimensional model, a two-dimensional icon, a text construct, a user screen name, etc. Although there are many different types of VUs, there are several features many VUs generally have in common. These features include, for example,                Shared Space: the VU allows many users to participate at once;        Graphical User Interface: the VU depicts space visually, ranging in style from 2D “cartoon” imagery to more immersive 3D environments;        Immediacy: interaction takes place in real time;        Interactivity: the VU allows users to alter, develop, build, or submit customized content;        Persistence: the VU's existence continues regardless of whether individual users are logged in; and        Socialization/Community: the VU allows and encourages the formation of social groups such as teams, guilds, clubs, cliques, housemates, neighborhoods, etc.        
As VUs become more complex and processing power, memory storage, and bandwidth increase, the number of ways in which users can communicate with one another in a VU has increased. For example, instead of relying on textual conversations, users can now audibly speak with one another while participating within a VU. This is particularly convenient during business meetings, lectures, and social gatherings within a VU.
As VUs increase in popularity the number of residents in a virtual location at any given time has increased. Understandably, this increase has resulted in an increase in audio communications. Currently these audio communications are being transmitted within VU regions at the same volume regardless of the source of the communication, how far the audio source is from the user, how many users are speaking at one time, etc. As such, an audio source ten feet away from a user may be heard at the same volume as an audio source two feet away from a user.